On Friday, share prices fell for both Smith & Wesson and Sturm, Ruger & Co., two major American gun manufacturers.

The losses were part of a half-month slide — and not simply confined to the aftermath of the mass shooting in Roseburg, Ore., that left 10 people dead on Thursday. It's an unusual negative stretch for both gunmakers, who have seen profits rise and their stock prices surge since President Obama took office in 2009.

Gun and ammunition sales have surged over the past several years on fears that Obama would push new control measures. Gun manufacturer profits have risen as well, through a run of mass shootings and the president's continued inability to persuade Congress to agree to any of his proposed gun legislation, such as expanded background checks.

The stock market shows that story. If you'd bought shares of Sturm, Ruger & Co. in 2009, they'd be worth about 10 times as much today. That's a slightly better return than if you'd bought Apple.